1. Field of the Invention
This invention relates to a load distributing apparatus for a facsimile storage and exchange system which stores image information from a facsimile unit and transmits the stored image information to a facsimile unit.
2. Description of the Related Art
In a conventional facsimile storage and exchange system, a plurality of storage and exchange units are disposed dispersively at corresponding positions, each of the storage and exchange units having a plurality of facsimile units allocated thereto and supervised thereby. If a facsimile unit transmits image information and destination information for that image information to its storage and exchange unit, the storage and exchange unit receives and stores the image and destination information, and relays the image and destination information to a further storage and exchange unit to which a facsimile unit represented by the destination information is allocated. When the further storage and exchange unit receives and stores the image and destination information, it transmits the image information to the facsimile unit represented by the destination information and supervised by the further storage and exchange unit.
Since the respective storage and exchange units supervise their allocated facsimile units separately, if the respective numbers of facsimile units supervised by the storage and exchange units are unbalanced, the quantities of information communicated among the storage and exchange units will be unbalanced. In order to cope with this situation, each storage and exchange unit is arranged to have slightly more than enough communication lines to process possible congestion with some leeway to thereby adjust the number of facsimile units supervised by that storage and exchange unit. Alternatively, the number of facsimile units supervised may be limited. Since, however, the number of facsimile units supervised by the corresponding storage and exchange unit cannot be changed according to the circumstances, there has been the problem that the quantities of information communicated or the respective loads on the storage and exchange units will be unbalanced. If a problem occurs in one storage and exchange unit, it is difficult for another storage and exchange unit to take over and supervise the facsimile units supervised separately in place of the former defective storage and exchange unit.
On the other hand, a single storage and exchange system may supervise many facsimile units in a concentrated manner. Such a storage and exchange system has, for example, a plurality of central processing units (hereinafter referred to as CPUs) as a control device, each CPU supervising a plurality of allocated facsimile units separately. However, if the respective numbers of facsimile units supervised by the corresponding CPUs are unbalanced, the respective loads on the CPUs will be unbalanced. Thus either each CPU supervises enough communication lines to cope with congestion or the number of facsimile units that may be supervised by one CPU is limited. Thus, problems arise because some of the communication lines are wasted or because the capability of the respective CPUs is not made the best of.